Reply: Discussing the place of TIPS in non-cirrhotic patients with chronic extra hepatic portal vein occlusion refractory to standard of care therapy
Authors: Gabriel M. Knight, Bartley Thornburg, Riad Salem
Journal: Hepatology (2023)

We read with interest Artru's letter responding to our study of TIPS with portal vein recanalization (PVR) in noncirrhotics with extrahepatic portal vein occlusion (EHPVO),1 where we report significant symptom improvement in 87% of patients, and an overall TIPS patency of 81% at 36 months.2,3 In brief, Artru's letter acknowledges the role of PVR-TIPS but suggests that similar rates of symptom improvement in a "similar population" with PVR alone may obviate the need for additional TIPS placement. We disagree with the contention that the populations were truly similar. The first difference relates to the rates of patients with underlying hypercoagulable disorders. Artru reported 39% as having prothrombotic disorders, but appears to include both inherited and acquired causes. Nearly 40% of our patients had previously-diagnosed inherited prothrombotic disease, and over 60% qualified as having prothrombotic disorders following the broader definition used by Artru. These patients are particularly vulnerable to re-thrombose after PVR and benefit from the increased outflow afforded by TIPS. We also note that a TIPS more easily facilitates re-interrogation of the portal venous system to allow for secondary intervention in cases of stenosis or occlusion. Second, in contrast to the 15/31 (48%) reported by Artu, none of our patients had EHPVO from pancreatitis or post-operative iatrogenic occlusions, scenarios where simply recanalizing the short-occluded segment without TIPS would make sense. To us, these represent physical/mechanical (simple stent re-establishes normal anatomy) rather than more complex physiologic occlusions [requiring inflow and outflow (TIPS) for patency]. Artru and colleagues also interestingly suggested that higher intrahepatic vascular resistance after PVR could inform the decision to place a TIPS and inquired about portal-caval pressure gradients. However, as visualized in the figure from our original manuscript, the majority of patients had significant extension of thrombus into the splenic and mesenteric veins, leaving little space to measure venous pressures. Hence, this information was not available. Finally, they cite an incidence of hepatic encephalopathy (HE) in 3 of 39 patients included our study as a disadvantage of our approach, but fail to mention that 2 of these 3 cases of HE were transient. Furthermore, the 1 patient with refractory HE was successfully treated with TIPS constraint (ie, additional stent placement within the TIPS to reduce the luminal diameter). Ultimately, the vast majority of our patients significant thrombus extended both caudally, into the splenic and/or mesenteric veins, and cranially into the intrahepatic portal venous system. In these patients, the brisk outflow afforded by a TIPS is critical in maintaining patency. It is our contention that primary stenting would not work in such cases given the intraluminally scarred, atretic and overall diseased intraparenchymal portal veins (Figure 1).FIGURE 1: TIPS venogram from 25-year-old noncirrhotic patient with EPVHO recently treated with portal vein recanalization-TIPS demonstrating characteristic atretic and diseased intraparenchymal portal venous system.We commend Artru on their recent publication of additional data demonstrating the safety and efficacy of minimally invasive portal venous intervention in this complex patient population. Moving forward, we will incorporate Artu's suggestions and plan to consider PVR alone in the rare cases of EHPVO with patent splenic and mesenteric veins and robust intraparenchymal portal venous systems.